The Fort Worth District of the US Army Corps of Engineers has issued a statement about the safety of their flood risk management reservoirs, stating that the facilities are operating as designed and intended, and "we are confident that they will continue to do so".
The statement was released in response to speculation about the state of Lewisville Dam in Texas, which the Corps acknowledges "has some known dam safety issues but is not at risk of failure".
After thorough assessment through the Corps' Dam Safety Programme, the Corps says it has identified Interim Risk Reduction Measures and a Dam Safety Modification Study which has been communicated to the public, and stakeholders on a continual basis. The studies will provide a solution to known seepage with potential for piping issues that were first identified by the Corps during the assessment in July 2005.
Lewisville is a well-designed and constructed dam, and it has been performing as designed. We're taking the necessary actions to make sure it continues in that mode, the Corps said.
Earlier during the flood events of May and June this year, many of the Corps' dams were put on a heightened monitoring status. At Lewisville Lake, the district's hourly surveillance team spotted a 49m slide on the upstream face of the embankment. A US$6.4M contract has been awarded to repair this with work scheduled to begin on 4 January 2016, and completion scheduled for May 2016.
"The reconstructed embankment will be protected by stone riprap on the upstream side and Bermuda grass sod on the downstream side," said Project Manager Mike Kingston. "As part of this effort, removal and replacement of a portion of the asphalt roadway and subgrade layers along the embankment crest will be required."